ceph: fix xattr rbtree search

Fix xattr name comparison in rbtree search for strings that share a prefix.
The *name argument is null terminated, but the xattr name is not, so we
need to use strncmp, but that means adjusting for the case where name is
a prefix of xattr->name.

The corresponding case in __set_xattr() already handles this properly
(although in that case *name is also not null terminated).

Reported-by: Sergiy Kibrik <sakib@meta.ua>
Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 6e12a6ba5f79..8c9eba6ef9df 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -219,6 +219,7 @@ static struct ceph_inode_xattr *__get_xattr(struct ceph_inode_info *ci,
         struct rb_node **p;
         struct rb_node *parent = NULL;
         struct ceph_inode_xattr *xattr = NULL;
+        int name_len = strlen(name);
         int c;
 
         p = &ci->i_xattrs.index.rb_node;
@@ -226,6 +227,8 @@ static struct ceph_inode_xattr *__get_xattr(struct ceph_inode_info *ci,
                 parent = *p;
                 xattr = rb_entry(parent, struct ceph_inode_xattr, node);
                 c = strncmp(name, xattr->name, xattr->name_len);
+                if (c == 0 && name_len > xattr->name_len)
+                        c = 1;
                 if (c < 0)
                         p = &(*p)->rb_left;
                 else if (c > 0)